1. Field of the Invention
The present invention generally relates to wireless communications and, more particularly, to improving the efficiency of frequency spectrum utilization.
2. Background of the Invention
With the continued proliferation of wireless communications and the increasing demand for wireless broadband access, the availability of various frequency spectrums over which to communicate has become scarce. With this in mind, the National Telecommunications and Information Administration (NTIA) and the Federal Communications Commission (FCC) have been investigating opening up certain frequency bands to expand commercial use in these frequency spectrums. Moreover, both the NTIA and FCC also are inquiring into new technologies that may be implemented to increase the efficiency of frequency spectrum utilization.
One relatively new technology for increasing the utilization of various frequency spectrums is cognitive radio. Cognitive radio is a paradigm for wireless communication in which either a network or a wireless network node changes its transmission or reception parameters to communicate efficiently while avoiding interference with other licensed and/or unlicensed users. This alteration of parameters is based on the active monitoring of several factors in the external and internal radio environment, such as radio frequency spectrum, user behavior and network state.
With the advantages of cognitive radio in mind, the NTIA is considering provisions to allow the use of cognitive radio opportunistically on a secondary access basis for the 410 MHz to 420 MHz frequency spectrum. Similarly, the FCC is considering provisions to allow the use of cognitive radio opportunistically on a secondary access basis for the 470 MHz to 698 MHz frequency spectrum. When using a frequency spectrum opportunistically on a secondary access basis, the designated frequency spectrum must only be used when there is an opportunity to use the frequency spectrum without interfering with communications of incumbent users, especially primary or licensed users. Thus, the use of cognitive radio is implemented to monitor the frequency spectrum to identify available channels, and only allow radio transmissions on the identified channels when the risk of such transmissions interfering with incumbent users is sufficiently mitigated.